Effect of End Borders on Plot Yield of Once-over Harvested Pickling and Fresh-market Cucumbers

Cucurbit Genetics Cooperative Report 7:31-32 (article 14) 1984

T.C. Wehner
Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695-7609

Yield of pickling and fresh-market cucumbers from plots harvested once-over is an efficient measure of yield in multiple-harvest trials (Wehner and Miller, unpublished data). Smith et al. (1) found the correlation between once-over and multiple-harvest yield to be less useful (r=0.31) in their test of 9 cultivars of pickling cucumbers. In the early stages of a breeding program where many families are being evaluated for yield, it would be efficient to use small plots harvested once-over as the selection method. Since seed supplies are usually limited, and because plots are small (1.5 x 1.5m was found to be optimal), trials are often run with plots separated by 1.5 m alleys to make it easy to identify the area to be harvested. It would, therefore, be important to know that end borders on plots do not affect the ranking of families for yield. The objective of this study was to determine whether yield of different genotypes of pickling and fresh-market cucumbers is affected by plot end borders.

Methods. Six cultivars and lines of pickling cucumbers (‘Calypso’, ‘Castlepik’, ‘Clinton’, ‘NCSU M201, ‘Pikmaster’, and ‘Tamor’), and 6 cultivars of fresh-market cucumbers (‘Bush Champion’, ‘Dasher’, ‘Early Triumph’, ‘Poinsett 76’, ‘Sprint 440’, and ‘Verino’) were chosen to represent the diversity of genotypes often used in breeding programs. The types represented included hybrid vs. inbred, gynoecious vs. monoecious, and tall vs. dwarf. The plots were planted on raised, shaped beds with 0.5 m tops and 1.5 m apart (center to center) on April 29 at the Horticultural Crops Research Station near Clinton, NC. Plots were 1.5 m long with either 1.5 m alleys or 1.5 m borders at each end. Harvest areas were marked with flags. Plots were harvested once-over when most of the plots reached 10% oversize (June 28 for the pickling cucumbers, and July 6 for the fresh-market cucumbers). Fruit were graded into marketable and cull and counted to determine total yield and yield per plant. The experiment design was a split-split-plot in a randomized complete block with 6 replications. Whole plots were the 2 crop types (pickling vs. fresh-market cucumbers), subplots were the 6 cultivars and lines, and sub-subplots were the 2 border treatments (ends vs. none).

Results. In the absence of end borders, the number of total and marketable fruit per plot was inflated 7 and 19%, respectively (Table 1). Plots with end borders had a higher percent of cull fruit as well (35% more). However, there was no significant interaction between cultivar and border treatment. Therefore, if end borders are left off plots, yield will be inflated, but the ranking of cultivars or lines will not be significantly affected. Thus, plant breeders can safely choose to plant small plots without end borders in order to make it easier to identify the harvest area, or to save seed where supplies are limited.

Table 1. Fruit yield of 12 cultivars and lines in 1.5m plots harvested once-over where plots had either 1.5 m of border or of alley at each end.^z

Cultivar or line	Plot end treatment	Yield (fruit/plot)		Culls (%)	Fruit per plant	Plants in harvest area
		Total	Marketable
Pickling Cucumbers
Calypso	Ends	20	18	8	1.71	12
	None	25	24	4	1.91	13
Castlepik	Ends	24	22	10	1.70	14
	None	26	24	8	2.00	13
Clinton	Ends	18	18	0	1.52	12
	None	17	17	0	1.49	12
M21	Ends	22	21	3	1.65	13
	None	24	22	5	1.70	14
Pikmaster	Ends	20	18	7	1.54	13
	None	25	24	6	1.81	14
Tamor	Ends	19	17	11	1.73	12
	None	23	21	8	1.76	13
Fresh-market cucumbers
Bush Champion	Ends	16	13	20	1.31	12
	None	17	15	12	1.41	12
Dasher	Ends	19	17	10	1.41	14
	None	23	21	7	1.79	13
Early Triumph	Ends	20	19	8	1.49	14
	None	27	26	3	1.92	14
Poinsett 76	Ends	17	14	17	1.28	13
	None	18	17	8	1.42	13
Sprint 440	Ends	20	18	9	1.58	11
	None	22	20	12	1.79	11
Verino	Ends	22	19	10	1.79	12
	None	27	24	11	2.11	13
F ratio (line x treatment)		1.06ns	1.20ns	1.52ns	0.58ns	0.69ns
LSD (5%)		3	3	4	0.27	1
CV (%)		17	17	65	20	12
Mean	Ends	20	18	9	1.60	13
	None	21	21	7	1.76	11

^zData are means over 6 replications.

Literature Cited

1. Smith, O.S. and R.L. Lower. 1978. Field plot techniques for selecting increased once-over harvest yields in pickling cucumbers. J. Amer. Soc. Hort. Sci. 103:92-94.